Synthesis of cobalt A2B triaryl corroles bearing methoxy or hydroxyl groups and their activity in electrocatalytic hydrogen evolution

Four A(2)B cobalt corrole complexes 1-4 appending two methoxy or hydroxyl groups on the 10-meso phenyl group had been synthesized. Four cobalt corroles showed high electrocatalytic activity for hydrogen evolution reaction (HER) in the organic phase and in the aqueous phase. The hydrogen evolution pathway was EECEC when using acetic acid as proton source. When trifluoroacetic acid was used as proton source, the hydrogen evolution route via EECEC or EECC depending on the concentration of trifluoroacetic acid. Cobalt corrole 4 showed the best HER performance with the k(obs) of 122.68 s(-1) in organic phase and the TOF of 832.2 h(-1) in aqueous phase respectively. The results suggested the phenyl hydroxyl group at the cobalt corrole peripheral may act as the proton relay group in HER and the o-hydroxyl of phenyl was better than m- hydroxyl for proton relay.

Automated summary

Four cobalt corrole complexes with substituents of methoxy or hydroxyl groups were synthesized and showed high electrocatalytic activity for hydrogen evolution reaction in both organic and aqueous phases. Cobalt corrole 4 exhibited the best hydrogen evolution performance.